Motion converter for screw thread comparator



Aug. 11, 1953 a. w. SWANSON MOTION CONVERTER FOR SCREW THREAD COMPARATOR Original Filed April 28, 1948 INVENTOR EPOP m JWA/VJ'O/K ATTORNEYS Patented Aug. 11, 195 3 UNITED STATES PATENT OFFICE MOTION CONVERTER FOR SCREW THREAD COMPARATOR Original application April 28, 1948, Serial No.

Divided and this application August 17, 1951, Serial No. 242,310

3 Claims. (Cl. 33-199) This application is a division of application Serial No. 23,732, filed April 28, 1948, Patent No. 2,588,431, and has to do with an invention relating to motion converter for screw thread comparators.

An object of the invention is to provide a comparator in which lost motion in the mechanism supporting the movable part of the thread gage in the die support may be eliminated.

Another object of the invention is to provide a comparator wherein motion converting means are provided in the mechanism supporting the movable part of the thread gage in the die support which is simple and positive in action.

Further objects and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawing in which,

Figure 1 is a side View of a comparator according to the invention, partially in section.

Figure 2 is an elevational view of the comparator viewed from the right of Figure 1.

Figure 3 is a sectional View taken on the line 33' of Figure 1.

Figure 4 is an enlarged fragmentary view, partly in section, of the thread gage and operating mechanism therefor.

Figure 5 is an elevational view of the upper portion of the die support.

As shown in the drawings, my improved comparator comprises a base 5 upon which is mounted a vertical post 6 having secured thereto a conventional indicator i that is adjustably mounted on said post by means of a clamping bar 8 having a clamping screw 9 thereon.

The said indicator is provided with the usual plunger Ill for operating the pointer II thereof to indicate the measurements of the parts. being gaged or compared.

A die support I2 is pivotally mounted in the post 6 for rotation about a vertical axis so that said support may be moved into a loading position wherein it is out of register with the plunger ID to permit loading the work into the dies without causing excessive operation of the indicator. The said support I2 is preferably C-shaped to provide an anvil portion I3 for supporting the lower portion IA of a thread gage and a head portion I5 in which is slidably mounted a plunger I8 which carries the upper half I! of the said thread, gage. The said plunger I6 is slidable in a bearing sleeve I8 and has an extension I9 thereon, the end of which engages with the plunger Ill for operating the indicator I. The said plunger I6 is normally urged downwardly to permit closing of the gage die halves I4 and I! by means of a spring 20 that is positioned between the end of the plunger I6 and a cap 2I that is threaded to the head I5.

The plunger I6 is operated to raised position for separating the die halves I4 and I! by means of a lever 22 which is pivoted to the support I2 by a pivot screw 23 and has an extension 24 thereon for operating a stud 25 that is connected to theplunger I6 and projects therefrom through a slot 26 in the side of the head I5 and the sleeve I8.

In order to provide for the necessary crosswise movement of the extension 24, relatively to the direction of movement of the plunger I6, due tothe movement of said extension around the axis of the pivot screw 23, the pin 25 is connected to said extension by means of an eccentric connecting disk 21 which is rotatably mounted in an opening 28 in the extension 24. The disk is provided with a flange engaging a shoulder in said opening for preventing the disk from sliding outwardly in the opening and the said disk is pre-, vented from sliding inwardly by abutment with the end of the pin 25 which fits within an offcenter recess 29 in said disk.

When the lever 22 is rocked downwardly by means of the thumb piece 30, the extension 24 is rocked upwardly, lifting the pin 25 and thereby raising the plunger I6 against the tension of the spring 20 to open the die halves I4 and I I. As the said pin is moved upwardly, the slot 26 will retain it against rotation so that its sliding movement is on a line running parallel to the axis of the plunger, while the movement of the connecting disk 21 is on an are from the axis of the pivotscrew 23.

To compensate for the diflerence in motion between the pin and the connecting disk, the said disk will rotate in the opening 28 and follow the pin 25. This will prevent lost motion, such as would result from a pin and slot connection, such as commonly used, and also provides a smoothness of operation that is permitted by the rotation of the connecting disk in the opening and which is not possible in a conventional pin and slot connection.

In order to pivotally mount the support I2 on the post 6, the said support is provided with a shank 3| that projects into a notch 32 in the said post and is pivoted in said notch by means of balls 33-33 which engage tapered annular shoulders in the opposite ends of a hardened shouldered bushing 34 on the pivotal axis of the shank 3i. The said balls 33-33 are mounted in supporting rods 3535 which have tapered shoulders in their ends for receiving the said balls 33-33.

These rods are slidably within a bore 36 that extends lengthwise through the post 6 and are adjustable lengthwise in said bore by means of thrust members in the form of screws 3I3l which are threaded to the walls of the recesses 3838 in said post and which are coaxial with the bore 36, so that they will retain the said bars against the balls 3333 for pivotally mounting the support I2.

The thrust members 3'I3'I may be adjusted to eliminate looseness in the pivotal mounting of the support l2 and also to provide the desired amount of tension upon the bearing balls 33-33 for permitting proper pivotal movement of the support without lost motion.

It will be understood that, in order to provide for maximum accuracy in the reading of the indicator I, it is necessary that there be no lost motion in the pivotal bearing for the supporting member I2 so that, when the said member is moved into register with the indicator and the extension I9 engages the plunger I0, the relation between said plungers will always be the same and the reading on the indicator will therefore be accurate.

In order to eliminate such lost motion, it is also necessary to eliminate play between the supporting rods 3535 and the walls of the bore 36. I, therefore, provide at the bearing ends of said rods a plurality of radial slits 39 which ex- 3 tend for a distance from the said ends and permit the rods to expand into tight engagement with the walls of the bore 36 when endwise pressure is applied to the said rods against the bearing balls 3333 by means of the thrust members 3'I--3"I and the said balls coact with the tapered shoulders at the ends of the rods to expand them into tight engagement with the bore and thereby eliminate side play and lost motion which could otherwise cause objectionable vertical rocking movement of the support I2.

The balls 33 are preferably provided with stems which extend into the axial bores in the rods and connect the said balls to the rods for facilitating assembly and disassembly of the comparator.

When the supporting member I2 is mounted on the post 6, the shank 3I is first inserted in the slot 32. The rods 3535, with the balls 33-533 thereon, are then inserted through the opposite ends of the post 6 into opposite ends of the bore 36 until the balls engage the tapered surfaces on the bushing 34. The thrust members 31-31 are then threaded into position against the ends of the rods 3535 and adjusted until the required amount of endwise thrust has been applied to force the said bearing balls into contact with the tapering surfaces of the bushing 34 with suilicient pressure to eliminate play or looseness in the pivotal connection between the said supporting member and the post 6. The pressure applied against said bearing balls will cause them to spread the ends of the rods 3535 so that the bearing portion of said rods fits tightly within the bore 36. This will prevent lateral movement of said ends and thus retain the bearing balls 33-33 directly upon the pivotal axis of the supporting member I2 to prevent movement of said supporting member off of said axis and thereby assure maximum accuracy in the operation of the device.

In order to facilitate the operation of my improved gaging device, I provide a stop, preferably in the form of a post 4 I, which is mounted on the base in position to engage the side of the support I2 and locate the extension I9 thereof into axial alignment with the plunger ID of the indicator.

In the operation of the device, the die support is first moved to the loading position or the position out of axial alignment with the plunger II. The lever 22 is then operated to raise the upper die jaw I l and permit insertion of the work to be gaged between the said jaw I1 and the jaw I4. Upon the said lever being released, the spring 20 will force the jaw II downwardly and thereby firmly engage the thread on the work piece between the die jaws IT and I4 and locate the said piece in position to be gaged or compared. The said supporting member is then swung on its pivotal axis against the stop 4|. When in this position, the extension I9 will be in axial alignment with the plunger II of the indicator and it will raise the said plunger I I slightly to rotate the pointer I I and show on said indicator the actual measurement of the work piece contained between the jaws I4 and II.

It will be understood that by adjusting the indicator I at the proper height on the post 6, by means of the clamping member 8 and adjusting screw 9, the plunger IO may be engaged by the extension I9 on the plunger I6 and be moved endwise for the required distance to permit proper operation of the pointer II for indicating the measurement of the work piece.

When the supporting member is swung into loading position, and the jaw I1 is moved by operation of the lever 22, the extension I9 will be permitted to move upwardly with said jaw without operating the plunger I0 of the indicator. The lever 22 being released before the supporting member I2 is swung back into gaging position and against the stop 4|, the said extension will have moved downwardly so that, when it engages the plunger I0 of the indicator, the plunger will be moved only for the slight distance required to indicate a discrepancy in the size of the work being gaged. This will eliminate excessive operation of the indicator, such as would be caused were the supporting member I2 not adapted to be swung into the loading position and the extension I9 permitted to move the plunger I0 for the full distance required to open the jaw II sufliciently to place the work in the die, which would result in rapidly revolving the pointer II and consequently causing excessive wear on the delicate mechanism of the indicator.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent is:

1. In a comparator for testing the condition of threads on articles, an upstanding post, a support positioned transversely of said post and mounted on said post for swinging movement about a vertical axis, an anvil portion and a head portion spaced vertically from each other on said support, a die positioned adjacent said head portion, and means connecting said die to said head portion for movement toward and away from said anvil portion, said means comprising a plunger arranged longitudinally of and mounted in said head portion for movement toward and away from said anvil portion and having the end adjacent said anvil portion carrying said die and having the end remote from said anvil portion projecting out of said head portion, a stud arranged transversely of and within said head portion and having one end fixedly secured to said plunger intermediate its ends and having the other end projecting through and beyond said head portion, a lever arranged exteriorly of and connected adjacent one end thereof to said head portion contiguous to said stud for rocking movement about an axis transverse of said head portion, and a disc rotatably mounted in said one end of said lever, there being an eccentrically disposed recess extending inwardly of said disc and receiving the projecting end of said stud.

2. In a comparator for testing the condition of threads on articles, an upstanding post, a support positioned transversely of said post and mounted on said post for swinging movement about a vertical axis, an anvil portion and a head portion spaced vertically from each other on said support, a die positioned adjacent said head portion, and means connecting said die to said head portion for movement toward and away from said anvil portion, said means comprising a plunger arranged longitudinally of and mounted in said head portion for movement toward and away from said anvil portion and having the end adjacent said anvil portion carrying said die and having the end remote from said anvil portion projecting out of said head portion, a stud arranged transversely of and within said head portion and having one end fixedly secured to said plunger intermediate its ends and having the other end projecting through and beyond said head portion, a lever arranged exteriorly of and adjacent one end thereof to said head portion contiguous to said stud for rocking movement about an axis transverse of said head portion, a disc rotatably mounted in said one end of said lever, there being an eccentrically disposed recess extending inwardly of said disc and receiving the projecting end of said stud, and a spring operatively connected to said plunger and said head portion for urging said plunger toward said anvil portion.

3. In a comparator for testing the condition of threads on articles, an upstanding post, a support positioned transversely of said post and mounted on said post for swinging movement about a vertical axis, an anvil portion, and a head portion spaced vertically from each other on said support, a die positioned adjacent said head portion, and means connecting said die to said head portion for movement toward and away from said anvil portion, said means comprising a plunger arranged longitudinally of and mounted in said head portion for movement toward and away from said anvil portion and having the end adjacent said anvil portion carrying said die and having the end remote from said anvil portion projecting out of said head portion, a stud arranged transversely of and within said head portion and having one end fixedly secured to said plunger intermediate its ends and having the other end projecting through and beyond said head portion, a lever arranged exteriorly of and connected adjacent one end thereof to said head portion contiguous to said stud for rocking movement about an axis transverse of said head portion, an extension on said one end of said lever, a disc rotatably mounted in said extension, there being an eccentrically disposed recess extending inwardly of said disc and receiving the projecting end of said stud, and a spring circumposed about said plunger and operatively connected to said plunger and head portion for urging said plunger toward said anvil portion.

BROR W. SWANSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 130,784 Bartram Aug. 27, 1872 1,337,018 Lockey et al. Apr. 13, 1920 2,586,114 Swanson Feb. 19, 1952 2,588,431 Swanson Mar. 11, 1952 FOREIGN PATENTS Number Country Date 260,609 Switzerland Aug. 1, 1949 552,634 Great Britain Apr. 16, 1943 

